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RESPONSE TO MAY 23, 1991 ADEQQACY REVIEW LETTER - STABILITY SENECA II-W MINE PERMIT C-82-057 PERMIT REVISION 1 July 18, 1991 A letter dated May 23, 1991 from Bruce Stover (CMLRD) to Larry Routten (CMLRD) addressed some concerns regarding facilities locations and potential slide problems. In addition to the location of proposed Pond 005, concerns were also expressed regarding the stability of certain portions of the Haul Roads G & H. Due to this letter, a field geological reconnaissance was conducted on May 30, 1991 of the Pond 005 drainage area. This included visually checking the area for signs of instability in and around proposed facility areas. Mr. James Pendleton (CMLRD) was in attendance during this site visit. Peabody Coal Company is currently re-evaluating the location of these facilities. Areas identified by aerial photography and field verified as potential or existing slide areas will require geotechnical investigation prior to final design or construction. Peabody is presently evaluating a proposed scope of work for subsurface investigation along the haul road alignments and will confer with CMLRD prior to investigative analysis. Peabody proposes to move the location of Pond 005 downstream to address the Division's concerns and comments about the suspected unstable slopes. The new general location, determined from site visits by Peabody and CMLRD, appears stable (see Exhibit 13-2). A general design plan for Pond 005 has been developed to demonstrate that sediment control is possible for the disturbed watershed (see Attachment 13-3). The detailed site design, with geotechnical information, will be submitted to the Division for approval by February 1992, so construction can be completed during the summer of 1992. CMLRD has also raised concern regarding the location of topsoil stockpiles SS, 00, II and TOB3 (overburden stockpile). Observations made during the May 30, 1991 site visit indicated that the proposed locations of II and TOB3 were on a landslide deposit, but that stability will not be a problem. The gentle ridge that these stockpiles are sited on appears to be stable (i.e., doesn't exhibit sloughing and faulting similar to the drainage area). The same concern was brought up about the siting of piles SS and 00. Due to the fact that they are in close proximity to obvious unstable areas, geotechnical investigations will be conducted prior to placement of these stockpiles. The alternative to this would be to re-site the stockpiles to an area that appears to be stable with minimal geotechnical investigation.